In the processing of tobacco, threshers are used to remove tobacco leaf or lamina from the stem portions of the plant. The mixed stem and leaf fractions are discharged from the thresher in a mixed stream of tobacco material. This stream is then typically conveyed to a classifier or separator where the lighter fractions such as lamina, are separated from the heavier fractions, such as stem or stem with leaf attached. One such separator is disclosed, for example, in U.S. Pat. No. 4,915,824.
To improve the integrity of the separated components, it has been proposed to link several classifiers together, with each discharging the heavy components directly into another classifier. Another proposal has been to project a mixed tobacco stream across a large chamber having a plurality of "lights" discharge openings fed by means of an inclined upward air flow. While these suggestions have been referred to as being "modular," they do not present modular apparatus in the true sense of the word since the respective separators and other components are not interchangeable.
Moreover, it has been observed that most tobacco classifiers must be cleaned out daily, consuming time and detracting from operation efficiency.
Accordingly, it has been one objective of this invention to provide a modular classifying apparatus wherein the modules and other components are interchangeable.
A further objective of the invention has been to provide self-cleaning modular classifier apparatus.
A further objective of the invention has been to provide a classifying module and infeed apparatus which can be combined or interchanged with other modules and infeeds for classifying light fractions from heavier fractions in a mix thereof introduced to each module.